function [ F ] = setF21( imu, avp, eth, T)

    global glv;
    VE = avp(4); VN = avp(5); VU = avp(6);
    vn = [VE; VN; VU];
    Lat = avp(7);
    wibbx = imu(1)/T; wibby = imu(2)/T; wibbz = imu(3)/T;
    fx = imu(4)/T; fy = imu(5)/T; fz = imu(6)/T;
    fb = [fx fy fz]';
    sinL = sin(Lat); cosL = cos(Lat); tanL = tan(Lat); secL = sec(Lat);
    Rmh = eth.RMh;
    Rnh = eth.RNh;
    wnin = eth.wnin;
    wnie = eth.wnie;
    wnen = eth.wnen;
    Cbn = a2mat(avp(1:3));
    
    M1  = [0 0 0; -glv.wie*sinL 0 0; glv.wie*cosL 0 0];
%     M1 = zeros(3,3);
    M2  = [0 -1/Rmh 0; 1/Rnh 0 0; tanL/Rnh 0 0];
    M3  = [0 0 VN/Rmh^2; 0 0 -VE/Rnh^2; VE*secL^2/Rnh 0 -VE*tanL/Rnh^2];
    F11 = -CrossMat(wnin);
%     F11 = zeros(3,3);
    F12 = M2;
    F13 = M1+M3;
    F14 = -[Cbn*diag([wibbx wibby wibbz]) Cbn];
    F21 = CrossMat(Cbn*fb);
    F22 = -CrossMat(vn)*M2 - CrossMat(2*wnie+wnen);
    F23 = CrossMat(vn)*(2*M1+M3);
%     F25 = Cbn*[Nax*eye(3) [0 0; Nay*eye(2)] [0; 0; Naz] eye(3)];
    F25 = [Cbn*diag([fx fy fz]) Cbn];
    F32 = [0  1/Rmh 0;  secL/Rnh 0 0; 0 0 1];
    F33 = [0 0 -VN/Rmh^2;  VE*tanL*secL/Rnh 0 -VE*secL/Rnh^2; 0 0 0];
    
    O33 = zeros(3,3); O63 = zeros(6,3); O123 = zeros(12,3);
    O39 = zeros(3,9); O66 = zeros(6,6); O129 = zeros(12,9);
    O36 = zeros(3,6); O912 = zeros(9,12); O1212 = zeros(12,12);
    
    F = [F11  F12  F13  F14   O36
         F21  F22  F23  O36   F25
         O33  F32  F33  O36   O36
         O63  O63  O63  O66   O66
         O63  O63  O63  O66   O66];

end

